// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SOCKET_CLIENT_SOCKET_HANDLE_H_
#define NET_SOCKET_CLIENT_SOCKET_HANDLE_H_

#include <memory>
#include <string>

#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "net/base/completion_callback.h"
#include "net/base/ip_endpoint.h"
#include "net/base/load_states.h"
#include "net/base/load_timing_info.h"
#include "net/base/net_errors.h"
#include "net/base/net_export.h"
#include "net/base/request_priority.h"
#include "net/http/http_response_info.h"
#include "net/log/net_log.h"
#include "net/socket/client_socket_pool.h"
#include "net/socket/connection_attempts.h"
#include "net/socket/stream_socket.h"

#include "net/tencent/net_logger.h"

namespace net {

// A container for a StreamSocket.
//
// The handle's |group_name| uniquely identifies the origin and type of the
// connection.  It is used by the ClientSocketPool to group similar connected
// client socket objects.
//
class NET_EXPORT ClientSocketHandle {
public:
    enum SocketReuseType {
        UNUSED = 0, // unused socket that just finished connecting
        UNUSED_IDLE, // unused socket that has been idle for awhile
        REUSED_IDLE, // previously used socket
        NUM_TYPES,
    };

    ClientSocketHandle();
    ~ClientSocketHandle();

    // Initializes a ClientSocketHandle object, which involves talking to the
    // ClientSocketPool to obtain a connected socket, possibly reusing one.  This
    // method returns either OK or ERR_IO_PENDING.  On ERR_IO_PENDING, |priority|
    // is used to determine the placement in ClientSocketPool's wait list.
    // If |respect_limits| is DISABLED, will bypass the wait list, but |priority|
    // must also be HIGHEST, if set.
    //
    // If this method succeeds, then the socket member will be set to an existing
    // connected socket if an existing connected socket was available to reuse,
    // otherwise it will be set to a new connected socket.  Consumers can then
    // call is_reused() to see if the socket was reused.  If not reusing an
    // existing socket, ClientSocketPool may need to establish a new
    // connection using |socket_params|.
    //
    // This method returns ERR_IO_PENDING if it cannot complete synchronously, in
    // which case the consumer will be notified of completion via |callback|.
    //
    // If the pool was not able to reuse an existing socket, the new socket
    // may report a recoverable error.  In this case, the return value will
    // indicate an error and the socket member will be set.  If it is determined
    // that the error is not recoverable, the Disconnect method should be used
    // on the socket, so that it does not get reused.
    //
    // A non-recoverable error may set additional state in the ClientSocketHandle
    // to allow the caller to determine what went wrong.
    //
    // Init may be called multiple times.
    //
    // Profiling information for the request is saved to |net_log| if non-NULL.
    //
    template <typename PoolType>
    int Init(const std::string& group_name,
        const scoped_refptr<typename PoolType::SocketParams>& socket_params,
        RequestPriority priority,
        ClientSocketPool::RespectLimits respect_limits,
        const CompletionCallback& callback,
        PoolType* pool,
        const BoundNetLog& net_log);

    // An initialized handle can be reset, which causes it to return to the
    // un-initialized state.  This releases the underlying socket, which in the
    // case of a socket that still has an established connection, indicates that
    // the socket may be kept alive for use by a subsequent ClientSocketHandle.
    //
    // NOTE: To prevent the socket from being kept alive, be sure to call its
    // Disconnect method.  This will result in the ClientSocketPool deleting the
    // StreamSocket.
    void Reset();

    // Used after Init() is called, but before the ClientSocketPool has
    // initialized the ClientSocketHandle.
    LoadState GetLoadState() const;

    bool IsPoolStalled() const;

    // Adds a higher layered pool on top of the socket pool that |socket_| belongs
    // to.  At most one higher layered pool can be added to a
    // ClientSocketHandle at a time.  On destruction or reset, automatically
    // removes the higher pool if RemoveHigherLayeredPool has not been called.
    void AddHigherLayeredPool(HigherLayeredPool* higher_pool);

    // Removes a higher layered pool from the socket pool that |socket_| belongs
    // to.  |higher_pool| must have been added by the above function.
    void RemoveHigherLayeredPool(HigherLayeredPool* higher_pool);

    // Returns true when Init() has completed successfully.
    bool is_initialized() const { return is_initialized_; }

    // Returns the time tick when Init() was called.
    base::TimeTicks init_time() const { return init_time_; }

    // Returns the time between Init() and when is_initialized() becomes true.
    base::TimeDelta setup_time() const { return setup_time_; }

    // Sets the portion of LoadTimingInfo related to connection establishment, and
    // the socket id.  |is_reused| is needed because the handle may not have full
    // reuse information.  |load_timing_info| must have all default values when
    // called. Returns false and makes no changes to |load_timing_info| when
    // |socket_| is NULL.
    bool GetLoadTimingInfo(bool is_reused,
        LoadTimingInfo* load_timing_info) const;

    // Used by ClientSocketPool to initialize the ClientSocketHandle.
    //
    // SetSocket() may also be used if this handle is used as simply for
    // socket storage (e.g., http://crbug.com/37810).
    void SetSocket(std::unique_ptr<StreamSocket> s);
    void set_reuse_type(SocketReuseType reuse_type) { reuse_type_ = reuse_type; }
    void set_idle_time(base::TimeDelta idle_time) { idle_time_ = idle_time; }
    void set_pool_id(int id) { pool_id_ = id; }
    void set_is_ssl_error(bool is_ssl_error) { is_ssl_error_ = is_ssl_error; }
    void set_ssl_error_response_info(const HttpResponseInfo& ssl_error_state)
    {
        ssl_error_response_info_ = ssl_error_state;
    }
    void set_pending_http_proxy_connection(ClientSocketHandle* connection)
    {
        pending_http_proxy_connection_.reset(connection);
    }
    void set_connection_attempts(const ConnectionAttempts& attempts)
    {
        connection_attempts_ = attempts;
    }

    // Only valid if there is no |socket_|.
    bool is_ssl_error() const
    {
        DCHECK(!socket_);
        return is_ssl_error_;
    }
    // On an ERR_PROXY_AUTH_REQUESTED error, the |headers| and |auth_challenge|
    // fields are filled in. On an ERR_SSL_CLIENT_AUTH_CERT_NEEDED error,
    // the |cert_request_info| field is set.
    const HttpResponseInfo& ssl_error_response_info() const
    {
        return ssl_error_response_info_;
    }
    ClientSocketHandle* release_pending_http_proxy_connection()
    {
        return pending_http_proxy_connection_.release();
    }
    // If the connection failed, returns the connection attempts made. (If it
    // succeeded, they will be returned through the socket instead; see
    // |StreamSocket::GetConnectionAttempts|.)
    const ConnectionAttempts& connection_attempts()
    {
        return connection_attempts_;
    }

    StreamSocket* socket() { return socket_.get(); }

    // SetSocket() must be called with a new socket before this handle
    // is destroyed if is_initialized() is true.
    std::unique_ptr<StreamSocket> PassSocket();

    // These may only be used if is_initialized() is true.
    const std::string& group_name() const { return group_name_; }
    int id() const { return pool_id_; }
    bool is_reused() const { return reuse_type_ == REUSED_IDLE; }
    base::TimeDelta idle_time() const { return idle_time_; }
    SocketReuseType reuse_type() const { return reuse_type_; }
    const LoadTimingInfo::ConnectTiming& connect_timing() const
    {
        return connect_timing_;
    }
    void set_connect_timing(const LoadTimingInfo::ConnectTiming& connect_timing)
    {
        connect_timing_ = connect_timing;
    }

private:
    // Called on asynchronous completion of an Init() request.
    void OnIOComplete(int result);

    // Called on completion (both asynchronous & synchronous) of an Init()
    // request.
    void HandleInitCompletion(int result);

    // Resets the state of the ClientSocketHandle.  |cancel| indicates whether or
    // not to try to cancel the request with the ClientSocketPool.  Does not
    // reset the supplemental error state.
    void ResetInternal(bool cancel);

    // Resets the supplemental error state.
    void ResetErrorState();

    bool is_initialized_;
    ClientSocketPool* pool_;
    HigherLayeredPool* higher_pool_;
    std::unique_ptr<StreamSocket> socket_;
    std::string group_name_;
    SocketReuseType reuse_type_;
    CompletionCallback callback_;
    CompletionCallback user_callback_;
    base::TimeDelta idle_time_;
    int pool_id_; // See ClientSocketPool::ReleaseSocket() for an explanation.
    bool is_ssl_error_;
    HttpResponseInfo ssl_error_response_info_;
    std::unique_ptr<ClientSocketHandle> pending_http_proxy_connection_;
    std::vector<ConnectionAttempt> connection_attempts_;
    base::TimeTicks init_time_;
    base::TimeDelta setup_time_;

    NetLog::Source requesting_source_;

    // Timing information is set when a connection is successfully established.
    LoadTimingInfo::ConnectTiming connect_timing_;

    DISALLOW_COPY_AND_ASSIGN(ClientSocketHandle);
};

// Template function implementation:
template <typename PoolType>
int ClientSocketHandle::Init(
    const std::string& group_name,
    const scoped_refptr<typename PoolType::SocketParams>& socket_params,
    RequestPriority priority,
    ClientSocketPool::RespectLimits respect_limits,
    const CompletionCallback& callback,
    PoolType* pool,
    const BoundNetLog& net_log)
{
    requesting_source_ = net_log.source();
    NET_LOG_SOCKET("ClientSocketHandle::Init group:%s", group_name.c_str());

    CHECK(!group_name.empty());
    ResetInternal(true);
    ResetErrorState();
    pool_ = pool;
    group_name_ = group_name;
    init_time_ = base::TimeTicks::Now();
    int rv = pool_->RequestSocket(group_name, &socket_params, priority,
        respect_limits, this, callback_, net_log);
    if (rv == ERR_IO_PENDING) {
        user_callback_ = callback;
    } else {
        HandleInitCompletion(rv);
    }
    return rv;
}

} // namespace net

#endif // NET_SOCKET_CLIENT_SOCKET_HANDLE_H_
